You see lightning flash followed 8.2 seconds later by the sound of thunder. The ambient air temperature is 12^°C. The speed of sound in air at 20^°C is 343 m/s. Approximately how far are you from the lightning?

Question

Quizplus · Accepted Answer

Using the formula distance = speed × time, we can calculate the distance to the lightning:
distance = 343 m/s × 8.2 s = 2810.6 m or 2.81 km
However, we need to take into account that sound travels slower in colder air. Using the formula v2 = v1 + 0.6T, where v1 is the speed of sound at 20°C (343 m/s), T is the temperature difference in Celsius (20°C - 12°C = 8°C), and 0.6 is the factor that represents the change in speed per degree Celsius, we can find the speed of sound in the given temperature:
v2 = 343 m/s + 0.6 × 8°C = 348.8 m/s
Now we can use the formula distance = speed × time again:
distance = 348.8 m/s × 8.2 s = 2859.36 m or 2.86 km
Therefore, the best answer is A) 2.77 km, which is closest to the calculated distance of 2.86 km.

You See Lightning Flash Followed 8